An example Windmill: a central grid with four outer grids pinned to its corners; the shared corner boxes (purple) are the four dark cells — shown as a box-level schematic.
Windmill Sudoku arranges five 9×9 grids as a pinwheel: a central grid shares each of its corner boxes with one of four outer grids, set at a windmill angle. Every grid is a full Sudoku, and the shared corner boxes must satisfy two grids at once.
The rule: five grids around a hub
Picture a central grid with four more grids pinned to its corners, spun like a windmill. Each shared corner box (purple above) belongs to the centre and an outer grid, tying all five together.
Solving strategy
- Attack the shared corner boxes. Each is constrained by two grids, so they crack first.
- Pass digits between grids. A value in a shared box is a given for both grids that own it.
- Solve each grid normally away from the overlaps.
- Work around the windmill. Progress in one grid opens its neighbours through the shared corners.
Common mistakes
- Forgetting a shared box serves two grids. Both must be satisfied at once.
- Not transferring digits. A corner-box value constrains the neighbouring grid immediately.
- Ignoring the ordinary rules. Every one of the five grids still needs 1–9 per row, column and box.
Can I play it here?
Not yet — Windmill Sudoku isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile:
- Try the closely related Samurai, which you can play right now.
- Browse all the Sudoku variants we do offer.
- Or print free puzzles from the printable PDF page.